Refrigerating apparatus for the storage and preservation of food, delicacies, and the like



March 5, 19 35.

REFRIGERATING APPARATUS FOR THE STORAGE AND PRESERVATION l. INGVARDSENEl AL 1,993,328

OF FOOD, DELICACIEYS, AND THE LIKE Filed July 28, 1935 FIG/7 PatentedMar. 5, 1935 UNITED STATES PATENT OFFICE Y REFRIGERATING APPARATUS FORTHE STORAGE AND PRESERVATION OF FOOD, DELlcAClEs, AND THE LIKEApplication July 28, 1933, Serial No. cacsz In Denmark January 28, 193312 Claims.

The invention relates to a refrigerating apparatus for the storage orpreservation of food, delicacies and the like. l

The use of such apparatus is at the present time increasingprogressively,-both for household purposes and for use in shops and thelike, and indeed to such an' extent that such apparatus must be regardedalready as indispensable for shops of a certain type. A disadvantageassociated with'the apparatus of known type in the last-named sphere ofapplication is, however, that it is not at the same time suitable forshowing or displaying the goods, because the apparatus is always in theform of closed cabinets (refrigerators), which is easy to understand inview of the fact that a good heat insulation is necessary.

In order to overcome this drawback, special refrigerators arealready'made for show windows and for other display purposes. The wallsof these refrigerators are of glass and quite transparent. In order thatthe necessary heat insulation may be obtained in this construction it isnecessary to use at least three glass plates, arranged one behind theother, for each wall.

The glass plates can then, however, easily be- Finally, all known formsof construction of refrigerating apparatus such as mentioned above areexpensive, especially also owing to cabinet structure itself.

According to the present invention, all these disadvantages are overcomeowing to the fact that the part of the refrigerating apparatus whichgives off the cold is constructed as a surface located freely in spaceon which the goods to be cooled can be placed so as to be freely exposedto view, and the cooling capacityof theapparatus is so great that thetemperature of.

the surface which may be made in any suitable form can be kept so lowthat white frost is formed thereon. I

Itwill be evident that the said surface may be used directly forinstance as a table, display board, or the like. The appearance of sucha surface is rendered particularly attractive by the valuable,particularly in many shops, restaurants white frost of course is alwayskept at at least 0 C., it is also possible to produce freezing in asimple manner. Whipped-cream tarts when placed directly on the coolingsurface, and in certain cases preferably on a metal dish, freeze on thelower side and thus retain a firm base, and thus the disintegrationwhich is so unpleasant is prevented.

In a typical embodiment of the invention the surface which gives off thecold contains chanrator of a compressor refrigerating plant or aguideway for a refrigerating medium (brine, for instance a solution ofsodium chloride).v When used as a table, display board or the like, theunder side of the plate including the channel this apparatus has thegreat nels, pipe-coils or the like which form the evaposystem ispreferably covered by a layer of heat insulating material and enclosedwith it in a frame so as to produce a good insulating effect.

The frame, made for instance of metal, should Various forms ofconstruction of the invention are illustrated in the annexed drawing, inwhich:

,Fig. 1 is a diagrammatical representation of a cooling apparatusaccording to the invention which operates with a compressor- Fig. 2shows a plan of a cooling plate used therewith.

Fig. 3 shows a method of attaching a pipecoil conducting the coolingagent to the surface plate.

Figs. 4, 5, 6 and '7 are cross sections of various forms of constructionof the frame embracin the cooling plate and the appropriate method of bya water cooler, in which case the fan 4 mostly may be omitted. The gas(SO2,NH3 or the like),

condensed by the compressor, passes through the piping 6 into the cooler5, from there passes through the piping 7 and then arrives in theexpansion valve (throttling nozzle or the like) 8. In the cooler 5 thegas shouldbecondensed to a liquid.- The gas expands in the expansionvalve 8 in known manner, thus producing cold which is given off to theplate 9. The expansion valve 8may, of course, be constructed in variousmanners and may, for instance, alsobe self-regulating. In this case theadjustment can be controlled either by the gas pressureor by thetemperature of the plate 9. After the working medium has given off itscold, it flows through the piping 10 to the suction side of thecompressor. The piping 10 is of such length, if necessary arranged inone or more coils 11, that the working medium is always able, even whenthe temperature of the surroundings is low, to give off its excessivecold to the surrounding air, (when this cannot be done completely by theplate 7) before it again reaches the compressor 3. At the same time itis thus also possible to give the plate an inclined position, forinstance, because the pipes can then yield sufliciently to permit it.

In-Fig. 1 the plate 1 is surrounded by a frame 12 which is insulatedfrom the plate and thus cannot assume a low temperature. The frameextends above the plane of the plate 9 to serve as a border or rim whichsharply delimits the frosted area that forms upon the refrigeratedplate.

Fig. 2 shows how the piping coming from'the expansion valve. may bearranged under the plate 9. The piping enters at 13 and then runs inbent formation along the lower side of the plate 9. The piping 10 leavesat 14. It is recommendable to combine the points 13 and 14 in such amanner that only one opening need be made in the table. It is mucheasier then to make the tubes fit airtight in the opening, which is verynecessary as will be pointed out hereafter. It is, of course," importantthat the pipe coil under the plate 9 should be in good thermallyconductive connection with the said plate 9. This can best be done bysoldering or welding (for example spot 'welding) when the pipe coil'ismade as a sepa- 3. Here, for instance the pipe 15 is soldered to theplate 9 by means of an ample proportion of an I alloy of low meltingpoint (for example Woods or Roses metal). The advantage of such an alloyis that the soldering can, for instance, be carried out by immersing theplate in hot water. With this-low temperature one may be sure that nobuckling, warping or other deformation of the plate 9 can occur, whichis very important as naturally the plate 9 must be kept as fiat aspossible.

It is evident that it is also possible by means of the refrigeratingplant to cool a solution of sodium chloride or the like to, forinstance, 15 C. below zero, and then cause this solution to run alongthe bottom of the plate 9 or to circulate therein. there is therefore acertain accumulation of cold available, and it is then also possible tofit the plate 9 on already existing refrigerating plants. Moreover, thelatter is possible in any case- Fig. 4 shows how the plate 9 can besecured in the frame 12. On the upper side this plate 9 is surrounded,for instance, by a strip of rubber 16 (in some cases for instance alsoby a rubber tube filled with cork) against which the plate 9 is pressedby means of thescrews 1'7. Immediately against the underside of theplate there are disposed small strips 18 of cork, supported by smallstrips 19 of wood, against which small plates 20 of fibre, bakelite orthe like are pressed. The screw 17 co-operates with a nut 21, likewisemade of insulating material such as fibre or the like. exactly adjusted,while a very great resistance is offered to the transmission of heatbetween the plate 9 and the frame 12. The resistance is furtherincreased in that the plate 9 is allowed to come into-contact with therubber 16 and the cork 18 only along a very narrow edge.

The space below the plate 9 and therefore about the pipe coil 22 isfilled with an insulating mass lower side. It is of importance ofcourse, that no air can enter into the space between the plates 9 and24, because if there would arise some air circulation, also white frostwould be formed there and this would decrease the cooling action at theupper side considerably, while besides a lot of condensation water couldbe formed within the insulating mass. Owing to. its large surface theframe 12 can easily assume the' temperature of the surroundings, andtherefore does not become covered with white frost, and does not evenbecome coated with moisture.v Preferably, the plate 9 is coated withnickel and then sanded, while the frame 12 may be coated with chromium,so that a very bright appearance is got together with the layer of whitefrost. The frame 12 is best made in the manner of extruded metal. Thespe- In this manner the plate 9 can be t tion. In this case the plate 9is clamped between two strips of rubber 25 and 26, which are held inplace by small blocks of wood 27, cork plates 28 being interposed ifnecessary.

Fig. 6 shows a further form of construction. Here also the plate isclamped between two strips of rubber 29, 30. In this arrangement theplate 9 can again be adjusted by means of screws 31. Further the rubberis as far as possible entirely enclosed at the upper side by anoverturned edge extended beyond this cabinet.

32 of the frame and at the lower part by a corresponding overturned edge33 of the bearingplate of the screw 31. In this manner the rubber isremoved from'sight as far as possible, and exposed as little as possibleto the action of moisture, while the heat transmission between the plate9 and the frame 12 is not substantially increased by the contact of theoverturned edges 32 and 33 with the plate 9, such contact being not morethan a point-to-point one.

Fig. '7 shows a construction in which all the component parts are ofbent metal. It is suitable for use, for instance, when rustless steel isused for the frames. The insulation is in the form of a rubber cord 34.In other respects the figure speaks for itself.

An easy manufacture of the plate is obtained if the surface plate 9 isgiven round corners. Then an endless strip of rubber provided with agroove is disposed under slight tension around the edge of the plate 9.The frame 12 may consist in this event of two parts, each of which isadapted to be thrust sideways over the plate, a groove in it surroundingthe rubber strip. Thereafter the two parts may be attached together, andthen they form a stiff frame in which the plate 9 is supported.

It may be added that the refrigeratingplates according to the inventionmay also be constructed,.for instance, as covers of an ordinaryrefrigerator cabinet, in certain cases as a cover Both the plates andthe cabinet can then be operated in a simple manner by the samerefrigerating mechanism. In certain cases a change-over device might beprovided to connect the refrigerating machine with the refrigeratorcabinet and the refrigerator plate as desired What we claim is:-

1. A device for the preservation and display of perishable goodscomprising a display surface freely exposed in open air, means forrefrigerating said surface, said means being of sufficient capacity tomaintain a coating of white froston said surface by moisture withdrawnfrom air circulating over said surface, a frame surrounding said surfaceand projecting above the same, and means insulating said frame from saidsurface whereby the frosted area of the surface is sharply delimitedfrom the unfrosted surface of the frame.

, 2. A device for displaying and preserving perishable goods comprisinga display surface freely exposed in open air, said surface constitutingthe upper member of a body containing passages constituting a conduitfor refrigerating medium, a refrigerating apparatus adapted to supplyrefrigerating medium to said passages in sufiicient quantity to maintaina coating of white frost on said surface, and a frame surrounding saidsurface and insulated therefrom whereby the frosted area of the surfaceis sharply delimited from the unfrosted surface of the frame.

3. A device for displaying and preserving perishable goods comprising adisplay surface freely exposed in open air, consisting of a plate ofheat conductive material, pipe coils positioned beneath said surface andin heat conductive relation thereto, a refrigerating apparatus adaptedto supply refrigerating medium to said coils in sufiicient quantity tomaintain a coating of white frost on said surface, a frame surroundingsaid I surface and projecting above and below the same,

heat insulating material between said plate and frame, and heatinsulating material substantially filling the space below said plate andwithin the downwardly projecting portion of the frame whereby thefrosted area of the surface is sharply delimited from the unfrostedsurface of the frame. 1

4. A device as defined in claim 3 wherein said display surface is ametal plate and the pipe coils are soldered to the under side of saidplate with a substantial amount of a low melting alloy.

' 5. A device for displaying and preserving perishable goods comprisinga display surface freely exposed in open air, means for refrigeratingsaid surface, said means being of sufficient capacity to maintain acoating of white frost on said surface, and a. frame surrounding saidsurface and sufiiciently insulated therefrom that it will not be chilledlow enough to cause the deposition of white frost thereon whereby thefrosted area of the surface is sharply delimited from the unfrostedsurface of the frame. I

6. A device for displaying and preserving perishable goods comprising afreely exposed display surface, means for refrigerating said sur-- face,said means beingof sufficient capacity to maintain a coating of whitefrost on said sur-- frigerating medium to said passages in sufllcientamount to 'maintain a coating of white frost on said surface, and aframe enclosing said body and insulating material, said frame beingsuificiently insulated from said body that it will not be chilled lowenough to cause the deposition of hoar frost thereon whereby the frostedarea of the surface is sharply delimited.

8. In a device for the preservation and display of perishable goods,the'combination with a substantially air-tight body comprising a frame,a plate forming the upper surface of the body, refrigerating conduitswithin the body and in heat-transfer relationship to said plate, a layerof heat insulating material within said frame beneath said plate andadjacent said conduits, and means insulating said frame from said plateto prevent cooling of said frame low enough for the deposition of hoarfrost thereon, of refrigerating apparatus for supplying a refrigeratingmediumto said conduits in quantity sufficient to maintain a coating ofwhite frost upon said plate by moisture withdrawn from air circulatingover the same. I

9. A device for displaying and preserving perishable goods comprising afreely exposed display surface, means for refrigerating said surface,said means being of sufiicient capacity to ported in threaded members ofinsulating ma- 1 terial attached to said frame below said plate.-

12. A device as defined in claim 9 wherein the insulating strip iscompressed between the plate forming the display surface and the frameby means of screws bearing on the under side 01 said plate throughfurther insulating material and 7 supported in threaded members attachedtosaid frame below said plate.

LTOHAN FREDERIK INGVAR INGVARDSEN. ERIK ANDERS DALSGAARD LEVRING.

